Early History of Glass

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. Stone-age man is believed to have used cutting tools made of obsidian (a natural glass of volcanic origin also known as hyalopsite, Iceland agate, or mountain mahogany) and tektites (naturally-formed glasses of extraterrestrial or other origin, also referred to as obsidianites).

The accidental discovery of how glass is created was suggested by the ancient-Roman historian Pliny (AD 23-79), as an accident by Phoenician sailors. It is possible that it was a result of shipwrecked sailors building fires for their cooking pots on blocks of soda (natron) on top of beach sand. By morning, the melted sand and soda mixture would have produced hardened glass. It was more likely that potters, from Egypt or Mesopotamia, discovered the brittle treasure independently, when firing their wares. Anyone who has painted hand-molded clay in school art classes with a variety of colored substances, knows that firing in the kiln will lead to hard-glassy coats. It is likely that the ancients tested many substances to discover which would generate the most durable and attractive coating for the otherwise dull and fragile pottery. Trial and error would have led to a glassy surface, which in turn would lead to the discovery of glass as an end unto itself.

A Craft is Born

The oldest fragments of glass vases (evidence of the origins of the hollow glass industry), however, date back to the 16th century BC and were found in Mesopotamia. Hollow glass production was also evolving around this time in Egypt, and there is evidence of other ancient glassmaking activities emerging independently in Mycenae (Greece), China and North Tyrol.

Some of the oldest glass on record dates back to the pre-Roman times. Solid beads and amulets have been found which were made in the year 2500 BC. Even though glass has been in existence for thousands of years, it wasn’t always considered an art as it is today. Its uses, for the most part, have been in functional pieces - containers to hold things. During the pre-Roman times, glassmakers were making vessels, but glass blowing had not yet been discovered. The vessel was made by wrapping hot glass around a core made of clay and dung. Sometimes the glassmaker would add color after the first clear layer was in place. After the glass cooled the core could be picked out, leaving what glassblowers nowadays call a vessel. Some of the earliest vessels date back to 1500 BC in Mesopotamia and Egypt. During that time glass was not yet a common household object.

Few people knew how to make glass, and only the pharaohs, high priests and nobles owned it. Both Middle Easterners and Egyptians were making mosaics out of glass. They would fuse rods of colored glass together to make a pattern. The resulting larger rod would then be heated and pulled out, causing the design to become smaller. Afterwards it was sliced and arranged into a mosaic. Knowledge of glass spread outward from Egypt and Mesopotamia mostly through the means of trade and conquer. Egyptian and Mesopotamian glass that dates back to the pre-Roman times have been found in the Mediterranean, Russia and France.

The Roman Empire

The Romans also did much to spread glassmaking technology. With its conquests, trade relations, road building, and effective political and economical administration, the Roman Empire created the conditions for the flourishing of glassworks across western Europe and the Mediterranean. During the reign of the emperor Augustus, glass objects began to appear throughout Italy, in France, Germany and Switzerland. Roman glass has even been found as far afield as China, shipped there along the silk routes.

It was the Romans who began to use glass for architectural purposes, with the discovery of clear glass (through the introduction of manganese oxide) in Alexandria around AD 100. Cast glass windows, albeit with poor optical qualities, thus began to appear in the most important buildings in Rome and the most luxurious villas of Herculaneum and Pompeii.

With the geographical division of the empires, glass craftsmen began to migrate less, and eastern and western glassware gradually acquired more distinct characteristics. Alexandria remained the most important glassmaking area in the East, producing luxury glass items mainly for export. The world famous Portland Vase is perhaps the finest known example of Alexandrian skills. In Rome's Western empire, the city of Köln in the Rhineland developed as the hub of the glassmaking industry, adopting, however, mainly eastern techniques. Then, the decline of the Roman Empire and culture slowed progress in the field of glassmaking techniques, particularly through the 5th century. Germanic glassware became less ornate, with craftsmen abandoning or not developing the decorating skills they had acquired.

China & The Middle East

There is less information about glass made in China during the time of the Roman Empire, though there is some glass from China that dates back to 221 BC – 220 AD. The Chinese made many engraved figures, eye beads and pi disks, which symbolized heaven. Blown glass was probably introduced to China by Persian glass artists.

The Middle-East was an interesting region because any kind of self indulgent or frivolous thing was forbidden by the Muslim religion. In the case of glass, it didn’t seem to matter. People still decorated their homes and holy buildings with glass. The Islamic people often used glass to imitate something of greater value, making the glass look in some cases like turquoise stones. It was done so well that people often had trouble telling what was a real stone and what was actually made of glass. Pictures and designs on glass vessels were made by first drawing out the design, and then chipping away at the glass leaving a raised pattern.

By this time Egypt had become part of the Muslim world, and made contributions to the art of glass enameling. The process for enameling involved painting a silver luster on the glass and then heating the glass up. The silver sort of fumed the glass, giving it brown and yellow colors. Enameling was often used in the glass lamps the Syrians made for mosques and Islamic houses of worship. In 1400, the Mongol conqueror Tamerlaine destroyed Damascus, and all production of Islamic glass ended abruptly. Tamerlaine sent all the Islamic glassmakers to Samarkand, the Mongol capital.

Sheet Glass Skills

The 11th century also saw the development by German glass craftsmen of a technique - then further developed by Venetian craftsmen in the 13th century - for the production of glass sheets. By blowing a hollow glass sphere and swinging it vertically, gravity would pull the glass into a cylindrical "pod" measuring as much as 3 metres long, with a width of up to 45 cm. While still hot, the ends of the pod were cut off and the resulting cylinder cut lengthways and laid flat. Other types of sheet glass included crown glass (also known as "bullions"), relatively common across western Europe. With this technique, a glass ball was blown and then opened outwards on the opposite side to the pipe. Spinning the semi-molten ball then caused it to flatten and increase in size, but only up to a limited diameter. The panes thus created would then be joined with lead strips and pieced together to create windows. Glazing remained, however, a great luxury up to the late Middle Ages, with royal palaces and churches the most likely buildings to have glass windows. Stained glass windows reached their peak as the Middle Ages drew to a close, with an increasing number of public buildings, inns and the homes of the wealthy fitted with clear or colored glass decorated with historical scenes and coats of arms.

Europe During The Middle Ages

In Europe during the dark ages, all aspects of life were diminished, and glass making was almost nonexistent. By the 12th century the Catholic Church was gaining power, and the dark ages were becoming a thing of the past. During the Middle Ages in Europe, glass production was primarily in making colored glass for the stained glass windows in the gothic architecture of that time. Most of the windows told religious stories, or depicted something from the Catholic bible. The Islamic Empire was still on the decline, and Venice was quickly becoming the center of all trade between the east and west. Through peaceful trading with the Middle East, glass finally made its way to Venice. Then in the early 1200’s, the Venetian Glassmakers’ Guild was formed. In 1291, all the glassmakers in Venice were forced to move to the island of Murano. This was done for a couple different reasons. It eliminated the fear of fires starting in Venice due to the glassblowers’ furnace, and more importantly, the glass industry could be easily controlled. Murano was only about an hours paddle from Venice, and gondolas were going back and forth constantly, but the glassblowers and their families were not allowed to leave the island.

The glass industry was very secretive, and the less people that knew how to make glass the better. If a glassblower did leave the island, it was a crime punishable by death. Despite the strict laws, many glassmakers did manage to leave Murano. It was these Murano refugees who brought the art of glassblowing to the shores of Tyrol, Vienna, Flanders, France and England. Some of the first Venetian glass was used for making rosaries. Beads from these rosaries have been found which date back to the 13th century. Venetians also revolutionized the way mirrors were made. For the first time mirrors were made of glass instead of polished metal. The glass used for making these mirrors had to be extremely clear. After the glass pane was made they would line the back with foil. As Venetian glass continued to grow, new kinds of glass began to emerge. The glassmakers of Venice invented a glass called cristallo that was incredibly clear. They added color to cristallo making dark blues, amethyst, red-brown, emerald green and milky white.

Europe During The Rennaisance

In the 17th century a book was published called L’Arte Vetraria (The Art of Glass) by Antonio Neri. For the first time ever the secrets of glass were out. L’Arte Vetraria had everything from how to make glass, to how to build the equipment, to how to actually blow glass. The diamond was becoming an item of trade, and soon diamond point engraving was developed. Glass was also used scientifically for the first time in telescopes and microscopes, and eyeglasses became greatly improved and much more useful.

Though Venice still had an influential hold on the glass industry, places in Spain, France, Germany, the Netherlands, England and Sweden were developing their own legend in what were known as forest glass houses. Some of the glasshouses were just temporary buildings, but some were used for years and years. The glassblowers in the forest developed a type of glass specific to the ingredients available in the forest. It was made using the ashes from the wood that was burned to heat the furnace. The ashes were called potash. They were purified and mixed with copper oxide, giving the glass a pale glossy green color. The glass houses influenced more than just the art of glass. The wood that the glassblowers cleared to heat their furnaces cleared land which was then used agriculturally. The forest glass houses produced mostly window glass and drinking vessels. Roemers were flared or rounded bowls, and humpen were the large vessels made for beer. The vessels were often very large, sometimes holding up to four quarts of liquid, and they had knobs protruding from the sides making them easier to hold, especially when the person drinking was in a drunken stupor.

In the Bohemian factories diamond point engraving was becoming more and more popular. Almost anyone could do it because the only requirement was that a person must be a good drawer. The Bohemian glassblowers invented a glass that was almost perfectly clear and easy to cut. It was made using chalk as the main ingredient, and soon people were using it all over the continent. Wheel engraving was also becoming popular and soon glass from Northern Europe became more coveted than Venetian glass.

Venetian glassblowers introduced fine glass to the people of England. There was a shortage of wood, and glassblowers were no longer allowed to use it as fuel. They began to heat their furnaces with coal, which created a whole new set of problems. The glassblowers had to come up with a ventilation system that would reroute the fumes from the coal, keeping them away from the glassblowers and the glass.

The English glassblowers invent what was known as black glass (really a dark green) in the mid-17th century. It was used to make thick walled vessels that were good for storage and easy to ship. Because they were so thick and dark, they blocked light that might damage the goods that were being transported. Because of these black bottles, England soon became the dominating bottle distributor.

In 1676 there came another breakthrough in glass industry. A man named George Ravenscroft developed a formula for making glass using lead. Ravenscroft was an English Glassmaker who had lived in Venice for many years. At the time he developed this new form of glass, he was secretly working in London. The new lead glass stayed workable for a much longer period of time than other types of glass, and because of its weight and clarity, people began to make vessels without decoration. More attention was paid to the form of the glass itself, not what was adorning it.

In 1607 the settlers of the Jamestown colony brought glassblowing with them to America. Glass was used mostly for just bottles and windows, and it was hard to distribute American made glass. Most of it was being imported from Germany. Caspar Wistar was the first man to successfully distribute glass in America, and after him came Henry Stiegal and then John Frederick Amelung. The first two men failed eventually because Stiegal put more money than he could afford into his glass, and Wistar failed due to the disruption of the revolution. Amelung manage to stay in business longer, and opened a large glass factory in Maryland in the year of 1784. This was also the year that Benjamin Franklin invented bifocals. Eventually, Amelung’s factory also failed. Even though it was hard, American production of glass continued to grow every decade of the 19th century. In the 1820’s the mechanical press was introduced to the glass industry, making production easier and faster.

In 1903, a man named Michael Owens invented an automatic bottle blowing machine that could produce millions of light bulbs a day. His bottle-blowing machine revolutionized the glass-container industry and is credited for eliminating child labor in the industry. He is the "Owens" in the Fortune 500 firms Owens-Illinois Inc. and Owens Corning, and the former Libbey-Owens-Ford Co. that is now part of Pilkington PLC, as well as in Owens Community College. Mr. Owens, who died in 1923, is among 41 "historically significant inventors" inducted into the National Inventors Hall of Fame 5/4/07.

Advances from France

In 1688, in France, a new process was developed for the production of plate glass, principally for use in mirrors, whose optical qualities had, until then, left much to be desired. The molten glass was poured onto a special table and rolled out flat. After cooling, the plate glass was ground on large round tables by means of rotating cast iron discs and increasingly fine abrasive sands, and then polished using felt disks. The result of this "plate pouring" process was flat glass with good optical transmission qualities. When coated on one side with a reflective, low melting metal, high-quality mirrors could be produced.

France also took steps to promote its own glass industry and attract glass experts from Venice; not an easy move for Venetians keen on exporting their abilities and know-how, given the history of discouragement of such behaviour (at one point, Venetian glass craftsmen faced death threats if they disclosed glassmaking secrets or took their skills abroad). The French court, for its part, placed heavy duties on glass imports and offered Venetian glassmakers a number of incentives: French nationality after eight years and total exemption from taxes, to name just two.

The 19th Century

In 19th century Europe, during the years between 1815 and 1848, a style called Biedermeier was all the rage and certainly the most fashionable. The term “Biedermeier” applied not only to glass, but also to life in general. It means plain and inoffensive, and was first used in a derogatory way. The glass of the Biedermeier era was certainly not plain, and I suppose for some people it could be offensive. The glass was lavishly cut, engraved and enameled, often depicting views of Vienna and idyllic scenes. Everything made during those years was influenced by the romantic and comfortable lifestyles of the times.

In 1845 the excise tax on glass was lifted, and in 1851 the Great Exhibition of the Industry of all Nations or the first World’s Fair was held. It took place in what was known as the crystal palace, a gigantic building that covered almost twenty acres of land. It was made using three hundred thousand panes of glass, all made by hand in one glass house. At around this time, styles were becoming more eclectic, and there was a revival of the older gothic and renaissance styles. Glass was used in people’s homes as drinking glasses, butter dishes, tea caddies, honey jars, flower vases and cheese and sugar dishes.

From Art Craft to Industry

It was not until the latter stages of the Industrial Revolution, however, that mechanical technology for mass production and in-depth scientific research into the relationship between the composition of glass and its physical qualities began to appear in the industry.

A key figure and one of the forefathers of modern glass research was the German scientist Otto Schott (1851-1935), who used scientific methods to study the effects of numerous chemical elements on the optical and thermal properties of glass. In the field of optical glass, Schott teamed up with Ernst Abbe (1840-1905), a professor at the University of Jena and joint owner of the Carl Zeiss firm, to make significant technological advances.

Another major contributor in the evolution towards mass production was Friedrich Siemens, who invented the tank furnace. This rapidly replaced the old pot furnace and allowed the continuous production of far greater quantities of molten glass.

Modern Flat Glass Technology

In the production of flat glass (where, as explained earlier, molten glass had previously been poured onto large tables then rolled flat into "plates", cooled, ground and polished before being turned over and given the same treatment on the other surface), the first real innovation came in 1905 when a Belgian named Fourcault managed to vertically draw a continuous sheet of glass of a consistent width from the tank. Commercial production of sheet glass using the Fourcault process eventually got under way in 1914.

Around the end of the First World War, another Belgian engineer Emil Bicheroux developed a process whereby the molten glass was poured from a pot directly through two rollers. Like the Fourcault method, this resulted in glass with a more even thickness, and made grinding and polishing easier and more economical.

An off-shoot of evolution in flat glass production was the strengthening of glass by means of lamination (inserting a celluloid material layer between two sheets of glass). The process was invented and developed by the French scientist Edouard Benedictus, who patented his new safety glass under the name "Triplex" in 1910.

In America, Colburn developed another method for drawing sheet glass. The process was further improved with the support of the US firm Libbey-Owens and was first used for commercial production in 1917.

The Pittsburgh process, developed by the American Pennvernon and the Pittsburgh Plate Glass Company (PPG), combined and enhanced the main features of the Fourcault and Libbey-Owens processes, and has been in use since 1928.

The float process developed after the Second World War by Britain's Pilkington Brothers Ltd., and introduced in 1959, combined the brilliant finish of sheet glass with the optical qualities of plate glass. Molten glass, when poured across the surface of a bath of molten tin, spreads and flattens before being drawn horizontally in a continuous ribbon into the annealing lehr.

Rouseau and Galle

The next major thing which revolutionized the way glass was seen did not occur until the 20th century. This is when the designer and artist became an important part of the glass houses. Two of the first designer/artists to actually work in glass was Emile Galle and Eugene Rouseau. They became well known for the glass they exhibited at the Paris Exhibition in 1878. Rouseau’s work was heavily influenced by Japanese art, and Galle was the beginning of the Art Nouveau style used in glass. It was a very graceful style, and so lent itself exceptionally well to the fluidity of glass. Louis Comfort Tiffany, of Tiffany’s, the jewelry store in New York, saw Galle’s work and fell in love. He too began to design glass, but did not actually blow the pieces himself. Maurice Marinot was the first artist to do all his own glass blowing single handedly. His vessels were massive and used subtle colors.

About one hundred years after Rouseau and Galle, after 1960, glass artists began to work in their own studios, outside of the factory environment. All of the artistic experimentation done in these studios is known as the studio glass movement. Rather than being defined by a philosophy or style, the studio glass movement is defined by the glass itself and how it works. The studio artists always made use of both hot and cold glass techniques including kiln fusing and stained glass. When the portable glass furnace was introduced it opened up many more avenues of glass work for the studio artists.

The studio glass movement is international and still developing. It is different from other glass movements because there is heavy emphasis on the artist and designer. Sometime they are one and the same, sometimes it takes a whole team of people to make a piece, as with the work of Dale Chihuly. He is a designer but not a glass blower. There is also a strong sense of sharing and community. While the glass world used to be very secretive, through the studio glass movement glassblowers are now sharing ideas and technical information. It started out as and American movement, and quickly spread to Europe, Australia and Asia.

History Continues to be Written

Although this brief history comes to a close nearly 40 years ago, technological evolution naturally continues. Not yet ready to be "relegated" to a history of glass are areas such as computerized control systems, coating techniques, solar control technology and "smart matter", the integration of micro-electronic and mechanical know-how to create glass which is able to "react" to external forces.