A Brief History of Glass
Beginnings
The origins of glass are lost in the misty origins of human civilization itself. Natural glass has existed since the beginnings of time, formed when certain types of rocks melt as a result of high-temperature phenomena such as volcanic eruptions, lightning strikes or the impact of meteorites, and then cool and solidify rapidly. Naturally occurring glass, such as obsidian, has been used since the Stone Age. Primitive tools chipped from natural volcanic glass appear to have been used since about 48,000 BCE. Beads of glazed stone have been dated to at least 4000 BCE.2
Hammesfahr (1968), 1
The first account of the origins of glass was written by the Roman encyclopedist, Pliny the Elder (23–79 C.E.). (As Commander of the Roman Fleet, perished attempting to rescue survivors of the volcanic eruption of Vesuvius. In his Natural History Vol. 36 he relates:
Pliny the Younger, Letter to Tacitus, Letter 6.16
“There is a story that once a ship belonging to some traders in natural soda put in here and that they scattered along the shore to prepare a meal. Since, however, no stones suitable for supporting their cauldrons were forthcoming, they rested them on lumps of soda from their cargo. When these became heated and were completely mingled with the sand on the beach a strange translucent liquid flowed forth in streams; and this, it is said, was the origin of glass”.
Pliny, 36:191, p. 151
Thus, according to Pliny, did humanity chance upon the recipe for making glass. Unfortunately, it is simply not possible to achieve the necessary heat to create glass with a campfire—a proper furnace is required, so Pliny’s account is definitely fanciful.
Glass isn’t made in Nature in a process that human beings can observe and imitate (like inside volcanoes). Manmade glass requires sand, and alkali (various choices for this), heated to temperatures that require a real furnace to achieve—expensive to build and operate. The ancient alchemist who was just trying combinations of materials in their furnace to see what happened (and that could be hazardous), thus discovering glass, would have to be our first Extraordinary Person in the history of the glass armonica.
For a thorough examination of ancient glassmaking technology, see Kurinsky.
Egypt
Man-made glass apparently originated in the pre-history of Eastern Mediterranean countries, perhaps Egypt. Mesopotamia seems to have had a flourishing glass industry around 2000 BCE, manufacturing non-transparent beads and other simple objects in fairly large quantities, with the occasional finely molded piece for the royal customer.
Phillips, Ency of Glass, p.20
During the reign of Tuthmosis III (1501–1447 BCE) Egypt invaded and conquered part of western Asia. Egypt’s first glass factory was found dating from that period, suggesting that one of the spoils of war might have been skilled glass craftsmen. In any event, Egypt was a synonym for luxury and culture in the ancient world, and although Mesopotamian glass making continued to flourish, it was the Egyptians who required and paid for the finest skills and materials, making Egypt the glass making capitol of the time. In fact, the earliest glass vessels that can be dated with some certainty are three turquoise blue vases with the cartouche of King Thothmosis III.
One in the British Museum, another in the Munich Antiquarium, and the third at the Metropolitan Museum of Art in New York. Phillips, p.11
Similar specimens from this period indicate glass-making reached high standards of efficiency. Egyptian vessels of colored glass found ready markets in the Middle East countries. This naturally led to the spread of glass-making knowledge, practiced in other countries bordering the Mediterranean.
Then in the fourth century BCE, Alexander the Great conquered the known world, and founded Alexandria in 331 BCE. Alexandria became a center of ancient world, and glass making ’followed the money’. Alexandrian glass products quickly captured export markets long been enjoyed by Egypt, and those exports reached as far as England and Scandinavia.
Phillips, p. 11
Apparently, Alexandrian glassmakers introduced their craft to Rome about the beginning of the Christian era.
It was about this time that we meet another of our Extraordinary People: an unknown crack-pot who had the crazy idea of taking a metal pipe, dipping one end of it into a pot of molten glass, and blowing. Mind you, glassblowing requires much hotter furnaces than other glassworking techniques. Furthermore, metal pipes were difficult to make and thus rare and expensive in ancient times. So our Extraordinary Person got their glass considerably hotter than was the norm, took their expensive metal pipe, stuck one end into the molten glass and blew a bubble. And humanity was forever transformed.
This technique was almost certainly invented in Syria in the first century of the Christian era. There is no way of knowing how this invention came about—this method is quite unlike any method employed before in glass — or in any other material then or since (for example: there is no such thing as ’bronze-blowing’). Glassblowing allowed the skilled artisan to create a far greater variety of glass objects in far less time than casting or other glass-making techniques. This unprecedented idea—blowing a bubble of molten glass — must easily qualify as one of humanity’s Truly Great Inventions.
The nature of the ancient glassblowing pipe itself is an interesting question. The pipe needs to be able to not only stand the heat, but also the heat differential—at one end will be molten glass, the other end will be at room temperature. The pipe also has to be about 1.5 meters long (5 feet)—shorter than that and the glassblower will be burnt trying to get the end into the molten glass; longer than that and the pipe is unwieldy, especially with a big blob of heavy molten glass on one end. (You have to start with more glass on the end of the pipe than will end up in the finished piece.) Thus the pipe also has to be rather strong, both physically and thermally-it almost has to be metal to meet all these requirements.
Although glass melts at about 650C (1200F), it needs to be considerably hotter than barely-melted to be ’blow-able’. Furnaces in modern glassblowing shops (with natural gas or propane fueled furnaces) currently keep the molten glass at about 1300C (2300F); ancient glassblowing shops (with wood-fueled furnaces) likely made do with lower temperatures.
The Egyptians around 2500 BCE were making copper pipes to a diameter a little under 2” by taking a flat piece of copper, rolling it into a pipe shape, and hammering the seam closed. Thus it’s clear that in ancient times they were capable of making, for example, a copper pipe that could have worked as a glassblowing pipe. Even in modern times, because molten glass is not only hot, but also corrosive, modern glassblowing pipes are expensive tools incorporating significant modern technology.
Sahura, Plumbing & Mechanical, July 1989. The earliest cast iron pipe appeared around 1500 (Koeble, F. & Hogan, W., Cast Iron Soil Pipe and Fittings Handbook, Cast Iron Soil Pipe Institute, 1994). Commonly used metals of ancient times include: lead which melts at 330C, brass at 925C, copper at 1100C, iron at 1150C (and glass at 650C), the melting point of alloys is considerably more complex. Modern pipe making received its big impetus from the making of gun barrels.
Curiously, although glass was known in India, China and Japan, they did virtually nothing to develop it. Glass technology has been a peculiarly Western pursuit until modern times.
Macfarlane, A. & Martin, G., “A World of Glass”, Science Vol. 305, Sept. 3, 2004, p.1407–8
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Glass Factoid: The first mention of glass in western literature (with the possible exception of the Bible, depending on whether you classify the Hebrew Scriptures prior to the Christian era as ’Western literature’) is in a speech by Cicero in 54 BCE in defense of Gaius Postumus at his trial:
‘Postumus’ ships were berthed in Puteoli and merchandise was talked about and seen. In reality, those goods were nothing more than cheap imitations made from paper, linen, and glass; and, although many ships were loaded with these, the whole lot together could not equal the debt.”
Pro Rabirio Posthumo XIV.40
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Glass Factoid: Glass is mentioned in the (King James) Bible in eight places:
Job 37:18 Hast thou with Him spread out the sky, which is strong, and as a molten looking glass?
Is. 3:23 (v. 18: In that day the Lord will take away the bravery of their tinkling ornaments about their feet. . . , and) the glasses, and the fine linen, and the hoods, and the vails.
I Cor. 13:12 For now we see through a glass, darkly; but then face to face: now I know in part; but then shall I know even as also I am known.
II Cor. 3:18 But we all, with open face beholding as in a glass the glory of the Lord, are changed into the same image from glory to glory, even as by the Spirit of the Lord.
Rev. 4:6 And before the throne there was a sea of glass like unto crystal; and in the midst of the throne, and round about the throne, were four beasts full of eyes before and behind.
Rev. 15:2 And I saw as it were a sea of glass mingled with fire: and them that had gotten the victory over the beast, and over his image, and over his mark, and over the number of his name, stand on the sea of glass, having the harps of God.
Rev. 21:18 And the building of the wall of it was of jasper: and the city was pure gold, like unto clear glass.
Rev. 21:21 And the twelve gates were twelve pearls; every several gate was of one pearl: and the street of the city was pure gold, as it were transparent glass.
Rome
With the rise of the Roman Empire, glass making once again followed the money—this time from Egypt to Rome, where it was embraced to a degree unrivaled even in modern times. The invention of glassblowing in particular coincided with the peak of Roman civilization—glass vessels were produced cheaply and in large quantities. Fine pieces became highly prized and symbols of wealth. “Its success was so great that it began to undermine its main competitor, ceramics. Glass was principally used for containers of various kinds: dishes, bottles, jugs, cups, plates, spoons, even lamps and inkwells. It was also used for pavements, for coating walls, for forcing frames for seedlings, and even for drainpipes. It is no exaggeration to say that glass was used for a wider range of objects than at any other time in history, including the present. It was especially appreciated for the way it enhanced the attractiveness of the favourite Roman drink, wine.”
Glass, A World History, Macfarlane, p.14
Of the five main uses for glass—jewelry (glass beads, etc.), vessels (like goblets and other domestic ware), windows, lenses, and mirrors—Rome developed jewelry and vessels most of all, although the other uses were known but not adopted to any great extent. (Although it might be a bit unfair to call it ’Roman Glass’ when Rome was really relying on foreign expertise and glassmakers ’acquired’ by the Empire.)
Window glass was apparently made by casting, and pieces of considerable size were made, but window glass was never particularly popular with the Romans—perhaps due to the temperate climate. The farther north, the more commonly are windows found. In Britain they were quite common after the Roman invasion and even into southern Scotland.
For a particularly stunning example of ancient glass casting, see the 8.5 ton slab of glass—the third largest ever made—cast in ancient times. Kurinsky, 214
It was in northern Europe that window technology developed and flourished after the fall of Rome. The Romans knew how to make glass mirrors, yet they preferred metal ones. Archaeology has only uncovered a handful of Roman glass mirrors.
Similarly, the use of glass to magnify objects was probably known. A little glass ball filled with water may have been used for fine work, such as engraving, but the Romans did not develop lenses or prisms.
Glass, A World History, Macfarlane, p.16
Glass making was at least attempted in every province that fell under the Roman yoke. And glass making persisted in the flotsam of the former Empire. Much of the production occurred on the edges of the old Empire. The Roman love of glass had spread as far as Afghanistan and the central Sahara, and as far north as Scotland and Scandinavian. “When the barbarians overran the Roman Empire, they had already absorbed glass as an essential part of their lives, and this tradition continued.”
Glass, A World History, Macfarlane, p.19
So glass making persisted. Different regions developed their own styles of glassware, of course. And windows became a high art form in the painted and stained glass windows of the medieval era. There are references to such windows from fifth century France onward; by 1000 painted glass is mentioned quite frequently in church records. The Benedictine order in particular gave impetus to window glass—they saw glass as a way of glorifying God through their involvement in its actual production in their monasteries, and injected huge amounts of skill and money into its development.
Glass, A World History, Macfarlane, p.20
Venice
But like a phoenix arising from the ashes, another city in formerly Roman Italy arose to be the next center of glass making—Venice.
It seems likely that the tradition of glass-making never died out in Italy, especially in the northern Adriatic area around Venice.Yet it was really from the thirteenth century that Italian, and particularly Venetian, glass-making began to influence the whole of Europe. Venice in particular was blessed by a bay that facilitated trade, and by lagoon sand and alkali plants necessary for glassmaking. By 1268 the fiolarii of Venice were apparently organized in a guild, and in 1271 the Capitolare was created: an agreement between the craftsmen, represented by their gastaldo who was elected from among their members, and the Republic’s officials for the surveillance of the crafts, I Guistizieri Vechhi. The Capitolare laid down the rules for the workings of the glass-houses:
Polak, 53
No glass house was to have fewer than three working-holes in their furnaces. These were to be fired with willow or alder. The working year was limited to the seven months from January to August, the rest of the year employed in the making—up of accounts, repairs and so on. The Capitolare also set out rules for the sales of products: No glass was to be imported into Venice. The export of products was to be carried out during that part of the year when the furnaces were idle, between August and January.
The main edifice of the Capitolare of 1271 remained standing for more than five hundred years, in fact until the final formal dissolution of the guilds of the Venetian glassmakers in 1806 with the fall of Venice shortly after Napoleon conquered Italy.
Polak, 53-54, 66
From early times glassblowers from Venice had set up their glasshouses at Murano, a lagoon island situated about five kilometers north of Venice; a rowboat could cover the distance in an hour. By a decree of 1292 the Grand Council of Venice encouraged the removal of all Venetian glass-houses to Murano, where the risks in the case of fire were smaller than in Venice itself. According to some historians, the glassmakers were encouraged to do so because, once established on the island, they were virtual prisoners, so strict were the regulations controlling the glass making industry against ’industrial secrets’ becoming known abroad. On pain of death no craftsman could leave Moreno or even teach a resident foreigner any of the trade secrets without express permission—which was seldom given. There are even stories of relentless assassins in pursuit of fleeing glassmakers-in one case, to the very gates of Prague, Czechoslovakia-over 500 km (300 miles) away.
Elville, 61
Zerwick, C., Short History of Glass, p. 50
Of course truth and legend are difficult to separate here, but it is safe to say that very harsh measures were involved, since their ’industrial secrets’ were of such enormous value. A register of 1454 specified the measures of the guild against fled glassworkers. First he was strongly urged to return, and would receive a full pardon and a job. If he refused, his relatives were thrown into prison. If he still refused, an assassin was assigned. Two cases of murder of this kind are mentioned in Venetian archives, and there were probably more.
Hannes, 19
As if assassins weren’t enough, the life of glassmakers wasn’t an easy one to begin with. According to a book in 1713:
Certainly no one could endure for long the strain of such work as these men have to do, nor could it be kept up except by robust men in the prime of life. During the process of making glass vessels the men stand continually half-naked in freezing winter weather near very hot furnaces and keep their eyes fixed on the fire and molten glass . . . their eyes have to meet the full force of the fire . . . they shrivel because their nature and substance . . . is burnt up and destroyed by the excessive heat.
Zerwock, History of Glass p. 58 ???
By about 1300 the removal of glassmakers from Venice to Murano was more or less complete, and to this day Murano has been the center for Venetian glassmaking. By the end of the sixteenth century, when Venice had about 170,000 inhabitants, Murano had a population of some 7,000, about 3,000 of which are believed to be directly concerned with glassmaking.
Polak, 54
Polak, 56
Furthermore, an edict in 1275 forbade the export of sand, alum and glass fragments.
Hannes, 19
By the early fourteenth century Venetian glass production was in full swing, and Venice’s vast fleet for war and commerce enabled her to trade as far as England and Flanders. Venice at this time was also “Queen of the Sea,” giving her ample facilities for exporting her manufacture to every part of the known world; and for a long period held the monopoly of supplying the cities of Europe with crystal glass.
Polak, 64
Reminisences, 24
The destruction of the city of Damascus (a great glass center) by the Mongolian war-lord Timur the Great in 1400 probably led to an influx of craftsmen to Italy, as may also have happened in 1453 when Constantinople finally fell to the Turks.
Glass, A World History, Macfarlane, p.20
One of the main innovations of the Venetian glass-makers was a type of glass called cristallo, invented between 1450 and 1460. It could be blown very thin, was colorless and free from flaws, and enabled glassmakers to make wonderfully elegant and intricate forms. Its purity and thinness was an object of fascination and desire.
Polak, 58
Glass, A World History, Macfarlane, p.21
Though Venetian control over the glassmakers and their families was strict, these craftsmen were highly regarded. Many were given patrician standing, their daughters being permitted to marry noblemen. The government of Venice also conferred the title of “Gentleman” (no idle title in those days) on all who became accomplished in the manufacture.
Zerwick, C., Short History of Glass, p. 50
Reminiscences, 24
So important to Venice was the glass-making craft that when Henry III of France visited Venice in 1574, it is said that his ship was greeted by glassblowers borne on a huge raft with a furnace in the shape of a mammoth sea monster spewing flames.
Zerwick, C., Short History of Glass, p. 50
Not surprisingly, this strict secrecy surrounding Venetian glass making would have invested the art with an air of romance; and legends, probably invented for the purpose, created a maximum of wonder to the uninitiated.
In fact, Venetian glass was so expensive that the modern practice of one glass per guest was actually unheard of as late as the 16th century. There might be only one glass to a table, so “a man should wipe his mouth on napkin or table-cloth.” If there was one glass to two guests, “one should empty every time one drinks so as to leave nothing for his companion”, a situation presumably alleviated by the cup-bearer refilling the glass.
English Glass, Charleston, 52
At about this time, even window glass was so expensive the glass panes were removed and put in a safe place when the occupants left the house for any time.
Technics & Civilization, Mumford, p. 124
But with the fall of the Republic of Venice in 1797, the glass art of Murano suffered a swift decline. We close this section with an extract from a “Familiar Letter” of James Howell, historian to Charles II, written in 1621:
Murano, a little island about one mile from Venice, is the place where crystal glass is made, and it is a rare right to see whole streets where on one side there are twenty furnaces at work. They say here, that although one should transfer a furnace from Murano to Venice, or to any of the little assembled islands about here, or to any other part of the earth beside, to use the same materials, the same workmen, the same fuel, and the selfsame ingredients every way, yet they cannot make crystal glass in that perfection for beauty and lustre as at Murano. Some impute it to the circumambient air, which is purified and attenuated by the concurrence of so many fires, that are in these furnaces night and day perpetually, for they are like the vestal fires, never going out.
Howell, The Familiar Letters of James Howell, May 30, 1621
Northern Europe
Glassmaking was certainly introduced into Northern Europe by the Romans at the latest, but the glassmaking tradition there may date even earlier, to Celtic times. These glass houses were located in forests. Forests were used for many purposes, including hunting for food and pleasure, for timber for houses and ships, and for fuel for domestic heating and commercial use—like glassmaking. Glassmakers were only rarely considered as primary claimants, more often they were delegated to hilly and remote country, where hunting was difficult and the timber not of prime quality. Sometimes the glassmakers were ’used’ to clear the land of forests to make way for agriculture. These glass houses must have been small, informal structures, worked as long as the fuel—supply immediately around the furnace lasted; when it was exhausted the furnace was left and another erected at a new location.
Hannes, 23
Polak, 38
Polak, 39
But around the time of the Renaissance, as communication improved and demand increased, these itinerant furnaces gave way to permanent glass houses. Glassworks were frequently located in areas where other industries were already established—glassmakers and potters worked side by side in Lorraine, while ironworks were interspersed with glasshouses in northern Bohemia. The industries depended on the same fuels and waterpower, and they could use the same communications lines to their markets. Relations weren’t always cordial, mostly because they were all competing for the same fuel. But at the same time they could exchange useful technical information, and the glassmakers needed both pottery and iron tools while the potters and ironfounders needed windows, bottles and drinking glasses.
Polak, 40
Polak, 41
From the early part of the sixteenth century, and especially from about 1550 onwards, great numbers of Italian glassmakers traveled to the north and began working there, permanently or periodically, in spite of the protests of the Venetian authorites. Some Italian towns (such as Altare on the Ligurian coast) actually encouraged glassblowers to go abroad and work for certain periods of the year.
Polak, 70–71
In general, with the rise of the Renaissance and the improving economic conditions that accompanied it, glassmaking ’ ´a la faon de Venise’ as it was called (“in the Viennese fashion”) slowly disseminated throughout Europe, from France to Scandinavia.
See Polak, 70ff for a good survey broken down by region
Alchemy
If changing common sand and burnt plants into a wondrous object of glass isn’t an alchemical transformation—then what is! If you can do that, changing lead into gold doesn’t seem so far fetched. Writing about glassmaking, Howell writes in June 1, 1621:
When I pry’d into the materials, and observed the furnaces and calcinations, the transubstantiations, the liquefactions that are incident to this art, my thoughts were raised to a higher Speculation. . .
Howell, 68
Alchemy in the ancient world was far more than ’changing lead into gold’, it was really proto-chemistry and proto-pharmacology. Alchemy certainly had its charlatans, but it also worked out—through long hard, and sometimes dangerous trial and error—processes for making now commonly used chemicals—like ’aqua fortis’ (nitric acid) and ’oil of vitriol’ (sulfuric acid). This practical knowledge was indispensable in the Alchemical Transformation of ancient alchemy into modern chemistry.
For an excellent survey, see Moran
Moran, 15
And one of the goals of ancient alchemy has been achieved. In 1980, Glenn Seaborg (1912–1999) transmuted several thousand atoms of lead into gold at the Lawrence Berkeley Laboratory, though the amount of energy used and the microscopic quantities created negated any possible financial benefit. For his work on transuranium elements (elements heavier than uranium, the vast majority of which are artificially created) he was  awarded the Nobel Prize in chemistry in 1951.
And much of the modern chemist’s apparatus comes straight out of the alchemist’s laboratory. Neri, in The Art of Glass (1612), the first book on glassmaking, says:
“some will, and perhaps with some reason, say that the invention of Glass was found out by the Alchymists; for they desiring to imitate jewels, found out glass; a thing perhaps not far from truth.”
Neri, 47
In the ancient world, the centers of alchemy followed the centers of learning in general. Alchemy appears in ancient Egypt—at the same time as Egyptian glass. When the center of glass-making moved to Alexandria—so did alchemy. And alchemy and glass migrated together to Rome.
Not surprisingly, the lines distinguishing Metallurgy from alchemy and glassmaking were rather unclear until the founding of modern chemistry. In fact, in the glass literature as late as the early 20th century, glass was still being referred to as another ’metal’. After all, it was produced by similar means: take a certain type of ’earth’ (sand, or ore) and heat it in a furnace which was as hot as the technology available then could make it, and a remarkably different substance emerges. And there is a tradition of an attempt to find an ’alloy’ of glass that was ’malleable’ (flexible) in the same way that other ’metals’ like copper are.
See The Forge and the Crucible, Eliade, M., U of Chicago Press, 1978
See, for example, ???
Neri, 48
With the fall of Rome, the craft of glass working survived in the West (no literacy required to work glass), but the more learned and literate alchemy did not. Along with mathematics, the works of Plato and Aristotle, and so much of Western learning, alchemy was preserved in the Middle East by the Arabs. With the fall of Damascus, and Constantinople in 1453, all sorts of scholars and artisans fled to the West. They brought with them mathematics, and new glass-making techniques, and Aristotle, and alchemy. This influx of new knowledge is generally regarded as one of the major impetuses of the Renaissance.
The first true alchemist in Medieval Europe was Roger Bacon (1214–1294), a Franciscan friar, considered one of the earliest advocates of the modern scientific method, but who also emphasized his reliance on the occult and the alchemical traditions. And he was intimately acquainted with the philosophical and scientific insights of the Arab world, one of the most advanced civilizations at that time.
The influx of Greek scholars into the West began much earlier, especially in the Northern Italian city-states that had started welcoming scholars in the eleventh and twelfth centuries. ??? The chancellor of Florence Coluccio Salutati Bethis cultural exchange in 1396 by inviting a Byzantine Scholar to lecture at the U. of Florence. It was the Italians’ hunger for Latin Classics and a command of the Greek Language which fueled the Renaisance.
wikipedia: fall of Constantinople ???
Glass is uniquely suited to alchemical (and chemical) research, because it is extremely chemically inert (doesn’t react with the chemicals inside), and you can also see what’s going on. [??? glass-makers also alchemists: Neri [Neri, 52] Agricola ]
So it’s not too surprising that the line between men who were working out new ways of coloring and working glass, inventing new kinds of glass and ways of coloring glass in their laboratories with furnaces, strange apparatus and chemicals, vs. doing alchemy in their laboratories with furnaces, strange apparatus and chemicals—well, what’s the difference?
Type ’alchemy’ and ’glass’ into your favorite search engine and see how many modern glass artisans still associate their art with alchemy.
Also, apparently a common belief of medieval and early renaissance glassblowers was that a Salamander lived in the furnace:
It was believed, too, that at certain times this wonderful being issued from his abode, and as opportunity offered, carried back some victim to his fiery bed. The absence of workmen, who sometimes departed secretly for foreign lands, was always accounted for by the hypothesis that in some unguarded moment they had fallen prey to the Salamander.
Visitors, too, whose courage could sustain them, were directed to look through the bye-hole to the interior of the furnace, and no one failed to discover the monster coiled in his glowing bed, and glaring with fiery eyes upon the intruder, much to his discomfiture, and effectually as to his retreat. [The Salamander occurs frequently in the alchemical literature—a creature that lives in fire.]
Reminiscences, 47
Furthermore, it was the custom for the workmen, in setting the pots of glass in the furnace, to protect themselves from the heat by dressing in the skins of animals from head to foot; to this ’outer’ garb were added glass goggles, thus creating the most hideous-looking monsters. “Show was then made of themselves in the neighborhood, to the infinite alarm of children, old women, and others.”
Reminiscences, 48
These furnaces were operated day and night. Not surprisingly, glass itself was regarded as having magical properties. Venetian glass in particular, when made under certain astronomical influences, would ’fly into pieces’ if any poisonous liquid was placed in them; and sales of vessels of this kind were made at enormous prices.[] In the 15th century, Philip Massinger would write of crystal glass:
Reminiscences, 49
Than hold one drop that’s venomous, of itself  It flies in pieces and deludes the traitor.
English Glass, Charleston, 50–51
Howell in a letter of June 1, 1621 repeats the same notion: “. . . a Crystal Glass . . . hath this property above Gold or Silver, or any other mineral, to admit no poison.” In the same letter he goes on to quote a popular saying: “The first handsome woman that ever was made was made of Venice Glass.”
Howell, 67
This would certainly be a highly valued feature in Italy in the 14th through 16th centuries under the Borgias (notorious for poisoning and intrigue), as well as the houses of the nobility in general throughout Europe. (It turns out there might actually be some basis in science for the claim: glass of the time may have had low stability to anything slightly corrosive—including poison.
See Neri, 14
The shattering of a Venetian glass by poisoned wine is described in the
novel The Mysteries of Udolpho (1794):
When the repast was over, they rose, and, each filling his goblet with wine from the gilded ewer, that stood beside him, drank ’Success to our exploits!’ Montoni was lifting his goblet to his lips to drink this toast, when suddenly the wine hissed, rose to the brim, and, as he held the glass from him, it burst into a thousand pieces.
To him, who constantly used that sort of Venice glass, which had the quality of breaking, upon receiving poisoned liquor, a suspicion, that some of his guests had endeavoured to betray him, instantly occurred, and he ordered all the gates to be closed, drew his sword, and, looking round on them, who stood in silent amazement, exclaimed, ’Here is a traitor among us; let those, that are innocent, assist in discovering the guilty.’
Radcliffe (1794), 1998, Terry Castle ed. Oxford World Classics, p.313
Fulcanelli goes so far as to assert, in his Le Mystère des Cathédrales, that alchemical ’secrets’ are displayed in plain view in the stain glass windows and statuary of various Gothic cathedrals.
Translated in Fulcanelli: Master Alchemist, Sworder, M., Brotherhood of Life, Las Vegas, 1990
We can easily see how the modern clear distinction between ’alchemist’ and ’chemist’ was not so clear at all in Elizabethan days from the following quote:
It [making iron] breedeth in like manner great expense and waste of wood, as doth the making of our pots and table vessels of glass, wherein is much loss, sith [since] it is so quickly broken; and yet (as I think) easy to be made tougher, if our alchemists could once find the true birth or production of the red man, whose mixture would induce a metallic toughness unto it, whereby it should abide the hammer.
Froissart, 323
England
The supremacy (and enormous profits) of Venetian glass was challenged by attempts to make glass of similar quality in England itself. Initial unsuccessful attempts were made as early as 1530, but the real beginnings of a crystal glass industry in England date from 1567.
English Glass, Charleston, 53
In England, Holinshed, in his Chronicles, published during the reign of Elizabeth I, says:
It is a world to see in these our days, wherein gold and silver aboundeth, that our gentility, as loathing these metals, (because of the plenty,) do now genrally choose rather the Venice Glasses, both for our wine and beer, than any of these metals, or stone, wherein before time we have been accustomed to drink, but such is the nature of man generally, that it most coveth things difficult to be attained.. . . The poorest endeavor to have glasses also if they may; but as the Venetian is somewhat too dear for them, they content themselves with such as are made at home. . .
2Friossart, p.275
John Greene of London in 1670’s asked that Venetian glasses being imported be made thick and heavy to withstand the hazards of transport by sea (which would make them completely unmusical).
Savage, Glass & Glassware, 54
Essentially, at about 1550 wine glasses were either extraordinarily expensive Venetian imports or locally made glasses—both too thick for music. But by about 1750, musically suitable wineglasses were sufficiently inexpensive and available that sets of musical glasses (with a couple dozen glasses in an instrument) had become common. This transformation of the wine glass in England came about from many factors. . .
The Rise of the British Empire
Elizabeth I (1533–1603) ascended the throne in 1558, and under her reign England was transformed from an impoverished country torn apart by religious strife to one of the most powerful and prosperous countries in the world. Under her reign England defeated the Spanish Armada in 1588—effectively establishing England as a world class sea power. This was good for English commercial shipping, which was good for English trade, and England prospered. A building boom ensued. This was good for English glass makers.
Elizabeth I was succeeded by James I (1566–1625), who ascended the throne in 1603, and continued her economic policies. Under his reign, the King James Bible was commissioned and published in 1611. Under the reigns of Elizabeth I and James I, Shakespeare (1564–1616) wrote and produced his plays.
The glass making industry continued to prosper. Much of this increase of demand for glass was for windows. All of England, and London in particular, was experiencing a construction boom, and needed glass. And glass windows were increasing in popularity. For example, “Hardwick Hall, more glass than wall” was completed by 1597. Occasionally a glass-house would be set up on the estate of a magnate building a new house which required extensive windows. And in 1666 the Great Fire of London, which raged for 5 days, destroyed approximately “thirteen thousand dwelling-houses, eight-nine churches, and St. Paul’s Cathedral” The good news is that the fire put an end to the Great Plague which had been tormenting the city. Reconstruction required more new windows.
English Glass, Charleston, 72–73
Churchill, II, 269
And glass was becoming popular in coaches as well. More importantly, England was beginning to see the rise of the middle class, which wanted its own glassware to emulate the nobility.
English Glass, Charleston, 107
Fuel
In 1550 glass-making and iron-making — both major industries in England — relied on wood for fuel. The growing demands for fuel for the growing glassmaking and iron mongering industries, for timber for shipbuilding, and for domestic building and heating was taxing the English forests. Beginning in 1585, Parliament passed a steady of stream of legislation that gradually prohibited the use of wood-fired furnaces. As glassmaking switched to coal, new coal-fired glass furnace designs received new patents, effectively rendering the previous patents obsolete. (England was the first to use coal to fire glass furnaces.) 1610 saw the first patent for a coal-fired furnace, only to replaced by a patent for a newer model a year later. Before coal, glassmaking patents had been in force for decades; now they were being rendered obsolete in a few years. This helped transform glassmaking from a stagnant monopoly to full-fledged competition. Also, once glassmakers were over the difficult transition, they found that coal was better than wood for firing glass furnaces.
English Glass, Charleston, 73ff
Howard, 21
English Glass, Charleston, 73???
Patents
’Patents’ during the reign of Elizabeth I (1533–1603) were really monopolies granted by the Crown. Initially these monopolies were intended to encourage the development of local industries by granting sole profits from local production as well as tariff—if not the outright prohibition — of imports. During the reigns of Elizabeth I through Charles I (1600–1649), these monopolies became a way of financially rewarding loyal subjects without depleting the royal treasury. Better still, these ’patents’ required an annual ’rent’ to be paid to the Crown, so not only was the loyal subject financially rewarded from the profits of their monopoly, but the Crown derived an income at the same time. Frequently the holder of a patent/monopoly might not even know anything about the technology of the industry over which he held a patent.
For example, in 1612 a satisfactory coal-fired glass furnace had been established. And by 1615 the technique for firing glass-furnaces with coal was sufficiently developed and in production to justify the granting of a monopoly. In ’The Proclamation touching glasses’ of that year, the use of wood for glass-furnaces was prohibited altogether, the import of glass from abroad was forbidden, and a royal monopoly for glassmaking in England, at an annual rent of £1000, was granted to a group of nine ’adventurers’. One of them, Sir Robert Mansell (1573–1656) soon bought out the others. Mansell was a vice-admiral in the Navy, and unacquainted with the glass industry.
Polak, 113–4
Price, 81
But the mood in England was increasingly against monopolies, because when a new monopoly was granted, long-standing businesses in that industry either had to submit to the newcomer monopoly holder or cease to exist. The ’Statute of Monopolies’ of 1624 largely eliminated them, conferring monopoly powers to first inventors only. Glassmaking was specifically exempted, but the writing was on the wall. In any event, there were sufficient loopholes in the Act that the problem ofmonopolies was not really solved at all.
English Glass, Charleston, 77
MacLeod, 15
The problem continued to worsen:
The practice of monopolies and all the evils it brought in its train rose to its greatest height in the reign of Charles I. The King’s almost frantic shifts for money and the illegalities and evasions he indulged in to fill his treasury rose to inordinate heights. Wine, soap, salt, and almost every article of domestic consumption fell into the hands of the monopolist and rose in price out of all proportion to the profit gained by the Crown.
Howard, 21
The Mansell monopoly lasted until 1640. In that year Charles I was forced to summon Parliament for the first time in eleven years, and among their first decrees was to condemn and abolish the glass monopoly of Mansell.
Polak, 114
In 1649, all remaining patent/monopolies issued by the Crown, including glassmaking patents, were rendered null and void when the King of England,  Charles I (1600–1649), was beheaded in the English Civil war and replaced by Oliver Cromwell, the “Lord Protector”. Upon Cromwell’s death in 1658 his son Richard briefly succeeded him, but soon abdicated. The monarchy was restored in 1660 when Charles II was crowned King. Charles II was all too mindful of the grief that the patent/monopolies had caused Charles I. Consequently, he rarely granted monopolies per se, leaving an essentially modern ’patent’ — a temporary ’monopoly’ granted to the original creator of a new technology — to evolve over the end of the 17th century into the 18th.
MacLeod, 24ff
Innovation In General
With the weakening of monopolies and the general growth of the English economy, the pace of competition and profits increased, and so did the pace of innovation. For example, Sir Kenelm (1603–1665) experimented with making stronger wine bottles, recommending that they be stopped ’close with Cork tied in’. Sir Kenelm was a glass-maker and alchemist as well as a diplomat and naval commander—he defeated French and Venetian fleets in the harbor of Scanderoon (on the southeast coast of Turkey) in 1628, making him a national hero. (Sir Kenelm was also a founder of the Royal Society, which very much concerned itself with glass, as well as other scientific matters. Benjamin Franklin would later be elected to this Society.) Bottle technology continued to develop, and around 1681 the corkscrew was invented, allowing the cork to be driven home flush. This “English bottle” was soon an enormous international success, since it allowed the storage and maturing of wine in the bottle. Furthermore, the wine bottle glass they had developed was not only strong, but almost opaque, which protected the wine from the destructive effects of light. Alongside the new English lead-glass (discussed below), “the dark glass bottle formed the spearhead of the English penetration of continental [European] markets, making England for the first time a net exporter of glass.”
English Glass, Charleston, 95–96
The Invention of Lead Glass
The invention of lead-glass (not to be confused with ’leaded glass’— windows made of smaller pieces of glass held together with lead, as in stained glass windows) revolutionized glass making in England and made her one of the glass-making capitols of the world.
In 1664 Charles II chartered the Worshipful Committee of Glass Sellers. At its formation the Company ’made and sold looking glasses or mirrors, but only sold (it did not make) drinking or table glass, bottles, stoneware pots and other stoneware goods which were made for them by Glass makers and Pot makers, principally English, though some were imported, mostly from Venice’. From its inception, the Glass Sellers’ Company was entrusted with the ’supervision of the Glass and Pot Makers’ trades’, and was ’empowered to search for and condemn all defective and deceitful ware’.
Charleston, 103–104
Frustrated with the virtual monopoly on the glass industry enjoyed by the Venetians, the Company of Glass Sellers commissioned George Ravenscroft (1618–1681) to experiment with native raw materials. [???] They wished to see England independent of foreign sources both for raw materials and finished glass.
In 1674 Ravenscroft petitioned the King for a patent for the making of a ’sort of crystalline glass resembling rock crystal’, and this petition was in a minute by the Attorney General ’that the glass is of a finer sort and made of other ingredients than any other glasshouses in England have used, and that the invention may be of considerable public advantage as the glasses thereby made equalize, if not excel, those imported from Venice and France.’ The patent was granted for a term of seven years, but already Ravenscroft had concluded an agreement with the Glass Sellers that they would ’take and buy the said Glasses of Ravenscroft. . .’
Charleston, 111
Lead glass is generally credited to George Ravenscroft (1618–1681), even though Ravenscroft—like so many patent holders—was himself not particularly knowledgeable about glass making—perhaps the knowledge came from one of the gaffers (chief glassblowers) in his employ named Giacomo da Costa.. And the making of various kinds of lead glass is described in The Art of Glass (1611), a book that was well known in England. But even though Ravenscroft wasn’t personally responsible for the various technical innovations that resulted in his lead glass, he certainly made it a commercial success.
Charleston, 111
Kurinsky, 388; Buckley, 25
Neri & Merrit, 15ff
Lead glass was originally known as ’flint glass’ because it was made with calcined flints instead of sand. These calcined flints were available in England, eliminating the need to import Venetian cuogoli. Lead glass was a far more brilliant, sparkling glass than had ever been made before. Besides the highly refractive appearance of lead crystal (which gives it its rainbow sparkles), lead glass was also much softer than regular glass, making it easier to engrave.
Buckley, 24
Charleston, 114
Ravenscroft’s lead glass incorporated three innovations: the first being the addition of lead. It had long been known that the addition of lead to glass gave it a high refraction; for this reason the Italians had used it when making imitations of precious stones. What was new in Ravenscroft’s use of lead was that he added it in greater quantities than anyone before. The second innovation was making the glass in coal-fired ’wind furnaces’ which produced a stronger and more stable heat than wood-fired furnaces could give. The third was the use of the covered pot for the molten glass, which concentrated the heat inside the pot and prevented the dust given off by the coals from contaminating the glass.
Polak, 117
Ravenscroft’s original formulation for glass was subject to ’crizzling’, a defect which produces an internal network of glistening lines and a gradual breakdown of the surface. “Crizzling is caused by instability in the glass, usually due at this period to the habit of boiling the fluxing alkali repeatedly in aneffort to purify it. This resulted in a reduction of the calcium content. Calcium is a glass stabiliser, and without a stabiliser the alkali is leached out of glass by atmospheric action, leaving  the slica network exposed and weakened.” Ravenscroft eventually solved this problem, as we can see from a statement issued by the Glass Sellers in the London Gazette 3 June 1676:
Charleston, 114
Wee under written doe certify and attest that the defect of the flint glasses (which were formerly observed to crissel and decay) hath been redressed severall months agoe and the glasses since made have all proved durable and lasting as any glasses whatsoever. Moreover that the usual tryalls wherewith the essay of glasses are made have bene often reiterated on these new flint glasses with entire success and easy to be done againe by any body, which proofs the former glass would not undergoe, besides ye distinction of sound discernible by any person whatsoever.
Charleston, 113
Here we see that stable and strong glass was still an ongoing area of research (which will have consequences for the development of glass music), and we see that unlike its predecessors, Ravenscroft’s glasses were musical by “ye distinction of a sound discernible by any person whatsoever”.
Lead glass certainly attracted the attention of foreign glassmakers. Some foreigners were already working in English glasshouses, and tried to establish lead glass abroad. The lack of proper fuel (coal) for the furnaces, and of proper clay for the glasspots, must have proved an almost fatal handicap to the foreigner attempting to make  English lead glass.
Buckley, 31
In 1674 Ravenscroft obtained a patent for his invention: lead glass. It was enormously successful. Ravenscroft died within a few days after expiration of his seven-year patent.
The Glass Tax
In 1745 Parliament passed an Excise on Glass—a tax by weight levied on the materials out of which lead glass was made. (This tax was increased in 1777, and again in 1822.) The predictable result of this tax was that glassmakers made their glasses thinner and lighter. “During the first forty-five years of the [18th] century, when there was no tax, and when glasses were sold by weight, there was every inducement to make simple massive glasses. During the period after 1745 there was an equal inducement to reduce the weight of the glass and to raise its value by other means.” In other words, make them thinner. So, due to the combination of all these forces—running out of forests and switching to coal, changes in the patent climate, the beginnings of rise of the British Empire and a middle class that wanted glasses for themselves, the invention of lead glass, the Glass Tax—all these combined to reduce the price of glasses[A dozen wine glasses could be bought in 1758 for 2 shillings—very approximately 2 ounces of silver., and to influence their shape into one conducive for music making. “The change was, of course, from an almost Venetian glass to one that is typically British. From a tall heavy glass, weighing often enough a solid pound, to a short light glass weighing a few ounces.”
Buckley, 22
Buckley, 40
Buckley, Old English Glass, 74
Buckley, 37
America
Glassmaking in America began at Jamestown, Virginia, in 1608. The English Board of Trade decided that glass making would be an ideal use for the limitless forests of the New World. As we have seen, England at this time was running out of forests, forced to switch to coal, and domestic glassmaking was struggling with the conversion. So a glass factory was founded in Jamestown, operating in the nearby
forest a little over a year after the first colonists arrived in England. This ”tryal of glasse” sent back to England that year was the first ’manufactured’ product of any kind, so it can be truly said that glass was America’s first industry. (Glass had already been made in the Western Hemisphere by Spanish craftsmen in Mexico around 1535.) It’s likely this first venture came to a close in the fall of 1609, and certainly came to a halt during ’The Starving Time’ in 1609 to 1610 when all but 60 of the 500 inhabitants at Jamestown died. Another venture was attempted in 1621 (less than a year after the Pilgrims landed at Plymouth) but was abandoned in 1624. The record suggests that little, if any glass was made.
Harrington, 3
Harrington, 9
Harrington, 10
A lack of technical knowledge on the part of the English financiers, the terrible hardships of the New World (including weather, famine, and the Indians), the quarrelsome natures of the glassblowers sent to Jamestown (good glassblowers had no reason to leave the ’Old World’, where demand for their skills was high) and the sheer distance to the markets in England all combined to make these first attempts at glass production in the colonies a failure, in spite of the abundance of fuel and good sand. Throughout the seventeenth and early eighteenth centuries the colonists were forced to import glass for their windows and glassware.
Spillman, 7
Official British policy forbade all manufacture in the colonies: the colonies were to produce raw materials for factories in England and provide a market for the finished goods. This included glassmaking. There were a few attempts at defying this policy. Caspar Wistar, a Philadelphia brass-button manufacturer who had immigrated from Germany, imported German glassblowers in 1739 and established a factory in southern New Jersey to make bottles and windows. This venture was successful enough to be left to his son, who however closed in 1781, probably because of the Revolution.
Spillman, 8
Another was by Henry William Stiegel, also a German. Like Wistar he also imported workmen (no other way to get them), like Wistar he had problems keeping them (some of whom wanted to start their own factories). Both Wistar and Stiegel appealed uncessfully to the patriotism of their fellow citizens to buy American instead of imported glass. Stiegel so overextended himself financially with his three factories that he eventually went to debtor’s prison in 1774.
Spillman, 8
After the Revolution there were no more restrictions against manufacture, but British mercantile policies still made it difficult for American manufacturers to compete. Finally, after 1790, Britian signed trade agreements with the new country; when the Acts of embargo and the ware of 1812 cut off the supply of British-made goods, American glassmakers were for the first time free of ruinous competition. There were setbacks to be sure, but glass production increased during every decade throughout the nineteenth century.
Spillman, 12
This brings our brief history of glass to approximately the time of Franklin. To be sure, both formulations of glass, and techniques for working it continued to  develop at a ever increasing rate. But we leave the continuing story of glass in modern times to others as we turn our attention to glass music. . .