History of Glass
The Discovery of Glass
There are several theories about how glass was first created and manipulated by man. Although most historians today think of these theories as legends, Pliny the Elder’s paradigm (23 A.D.-79 A.D.) is so popular that it deserves mentioning.
“Merchants on a moored merchant ship laden with nitrum were preparing their meal on a beach. They did not have stones to prop up their pots, so they used lumps of nitrum from the ship. This mineral fused with the sands of the shore where upon streams of a new translucent liquid flowed, resulting in the discovery of glass.”
Historians believe that the invention of glass was more deliberate than the previously mentioned
legend. The Phoenicians, a group of people living in Mesopotamia, the current Syria, Iraq, Turkey and Israel, used glass to glaze ceramic objects such as cups, vases, plates, etc. as early as 3000 B.C. Since they liked the properties and appearance of glass, they kept developing this glazing material until they were able to create items entirely from glass. From here furnace structures developed in Mesopotamia, as early as 2700 B.C. Glass products discovered include glass beads and seals.
Glass became a popular art form in jewelry to mimic gemstones in colors not found in nature. These glass gemstones were even more expensive than the real products due to the complexity of making them. This is indicated in one of the world’s oldest living texts, the Bible. “Gold and glass cannot equal it, neither shall it be exchanged for jewels of fine gold.” Job 28:17
Natural glass is not clear at all but instead has a faint greenish or bluish tinge from the copper and iron oxides in the sand. Today, imperfections are filtered out of the glass and lead oxide or other additives are used to turn the glass clear.
Glass eventually evolved into utilitarian use for items such as small vases, cups, bowls and other everyday objects. Oftentimes, sand particles would remain in the finished product due to the imperfection of the refining process.
By the 1st century B.C. the art of glassblowing had been discovered in the far eastern reaches of the Mediterranean. This new technique allowed the glass workers to create even more extravagant and creative forms with which to explore their craft.
It is commonly believed that the first glass blowing tubes, called blowpipes, were created from clay. This would have made glass working extremely uncomfortable as it is impossible to create a long enough pipe fashioned from clay to protect the artist from the 1000 degree Fahrenheit hot glass. Soon, metal blowpipes were created to greatly reduce the threat of harm and allowed the artist to create larger and heavier pieces.
Venetian and Murano Glass
By the 8th century, Venice had become the glass capital of the world. At that time, Venice traded heavily with Eastern Mediterranean areas, North Africa and the Middle East. These influences brought new techniques and ideas to the artisans of Venice and they used these to create exceptional pieces of art. The conquest of Constantinople in 1204 during the Fourth Crusade is believed to have been an important event that brought Venice additional glassblowing techniques for the glass industry.
By the 13th century the glass artists had combined all their knowledge into unique and proprietary production skills. Venetian glassmaking became the leading source for fine glass in Europe and a major source of trading income for the Republic of Venice. In 1291, the government of Venice banned glass furnaces from the central islands, relocating them to Murano, a small group of islands about two miles north of Venice. Until recently, most historians have assumed that the order was a result of fear that the fires of the glass furnaces might create a raging inferno among the largely wooden structures of crowded Venice. However, it has been plausibly suggested that the move was made in order to hide the master glassblowers and prevent the many foreigners who visited the city from gaining the valuable glassmaking techniques. Essentially, the glassblowers became virtual prisoners, isolated from contact with anyone who might divulge their production secrets to potential competitors abroad. It is for this reason that Venetian glass is now known as Murano glass.
The glass production in Murano was so important for the Venetian economy that the government went so far as to forbid glassworkers from traveling outside of Murano. There were even claims, though unsubstantiated, of Murano glassworkers who left to work in other parts of Europe, who were assassinated when they refused to return to Murano.
Most of the glass from this period, though luxurious, was still utilitarian. Mirrors, for example, were major revenue producers, but beautiful and complicated decorative objects were produced as well, often exhibiting complex new techniques developed by Murano’s extraordinary artisans.
By the 15th century, Murano glass artisans started experimenting with different additives to create a clear type of glass, called “cristallo,” from which the English word “crystal” is derived.
The “Cristallo” glass that the Venetians created was an Italian soda glass and was as clear as they could get their glass. Usually it was still a pale yellow since it was difficult to make glass completely transparent. It was made with a plant called “Barilla” which grows in the salt marshes. The Barilla lowered the melting temperature of the glass, enabling it to be formed into myriad shapes. It was thin and brittle and could only be engraved using a diamond point. This was the popular type of glass in the 15th and 16th century and heavily exported until lead crystal was invented in England. Today’s soda glass is created with chemical soda, which has eliminated the need for the expensive plant ingredients in glassmaking.
By the 16th century serious competition began to emerge, particularly in France and Moravia (a region located in the current Czech Republic). At the same time, changing trade routes began to undermine Venice’s strategic trading advantages. As a result, the decline in Venice’s general economical importance was mirrored by the gradual, long-term decline of its glass industry on Murano.
It was not until 500 years later, between 1860 and 1960, that Murano’s glass art underwent a remarkable revival, which brought Murano’s glass producing firms back to leadership in the production of decorative glass objects.
German Glass Art
In the 12th century, a glass technique that had not seen much popularity became revitalized when a German monk named Theophilus, who was also an artist and a metalsmith, created beautiful stained glass windows. Theophilus wrote a text titled ”On Diverse Arts” where he described how he carefully studied glaziers and glass painters at work in order to provide detailed instructions for creating windows of “inestimable beauty.”
A window’s pictorial image is created by arranging different pieces of colored glass over a design drawn on a piece of board. If fine details such as shadows or outlines are required, the artist paints them on the glass with black paint.
To assemble the window, pieces of colored and painted glass are laid out on the design board, with the edges of each piece fitted into H-shaped strips of lead known as cames. These cames are soldered to one another such that the panel is secure. When a panel is completed, putty is inserted between the glass and the lead cames for waterproofing. The entire composition is then stabilized with an iron frame called an armature and mounted in the window.
Another important contribution to glass and glass art that came from Germany is the invention of the first borosilicate glass by the Jena Glasswerke in 1887, the company where Fräbel learned his trade as a scientific glassblower.
In 1884, Dr. Otto Schott founded the glass production company “Schott und Genossen,” together with Dr. Ernst Abbe and Carl Zeiss in Jena, Germany. Later this company was renamed “Jenaer Glaswerke,” after the area in which it was located. Dr. Schott invented the first type of Borosilicate glass, also called “Jenaer Glas,” in 1887. This new type of glass had the ability to withstand extremely high temperatures, enabling it to be used in gas and petroleum lights. This invention was the major breakthrough for “Jenaer Glaswerke,” and in that same year the company made its first profit. From its inception until 1909, Jenaer Glaswerke sold over 30 million gas and petroleum light glasses.
The property to withstand both high and low temperatures made Borosilicate the ideal material for the creation of glass instruments for scientific and chemical purposes. Because of this invention, Jenaer Glaswerke became one of the largest suppliers of scientific glass instruments in the world.
This Borosilicate glass had another advantage: It could be heated numerous times, which made it a perfect material from which glass sculptures could be created, as the artists of the Fräbel Studio have done.
The Invention of Crystal Glass
As described in an earlier chapter, it was the Venetians who created the first type of crystal, which they called “cristallo.” Crystal glass refers to a clear type of glass, independent of the additives used to get the clarity of the glass. The Venetians initially used a plant called Barilla to get the glass clear and malleable. This first crystal glass gained huge popularity and became a successful export product for the Venetians in the 15th and 16th century.
In the middle of the 16th century several leading glassblowers moved from Murano to London, where they found the favor of Queen Elizabeth I who enjoyed the glass pieces they created. The Venetian influence and the Queen’s support were the basis for the discovery of lead glass in the following century.
Four centuries later, England is ruled by Queen Elizabeth II, who besides sharing her predecessor’s name, also shares her passion for glass. In her extensive art collection, one can find an especially for her created Fräbel sculpture.
In 1673, George Ravenscroft established his own glass factory in London. Shortly thereafter, in 1675, he patented a process for making “flint glass” or “lead crystal” by adding lead oxide to Venetian glass. Ravenscroft discovered that the addition of lead oxide to glass during the melting process improved the clarity of the glass, while lowering the melting point, therefore, making it easier to work with. Such problems as the introduction of a bluish tinge and “crizzling” of the glass were encountered in the early stages of his work. Increasing the lead content in the crystal reduced or eliminated these issues. He continued experimenting with the chemical composition of glass, and eventually eliminated the imperfections. The practice of cutting the lead crystal glass became popular shortly after the invention of lead crystal. In the 18th century, England saw a boom in glass factory production; however, a government excise tax on glass dampened profits and factory manufacturers tried to escape this tax by moving their factories to Ireland. During this period, Ireland became the new center for production of lead crystal in Great Britain. Crystal glass factories elsewhere in Europe thrived throughout the 19th century in France, Sweden, Austria and the Czech Republic.
New Uses for Glass
In the 20th century innovative uses for glass were invented. Today medical scientists use a glasslike material for artificial dental fixtures and bones. An advantage to using glass as opposed to mercury or metal is that glass is nontoxic and rarely rejected by the human body.
Recently, medical breakthroughs have been achieved in the United States by utilizing small glass radioactive spheres to treat liver cancer. Microscopically small glass spheres with a diameter measuring less than a follicle of hair are radiated and brought into the liver where they get “stuck.” Millions of these glass spheres give off high levels of radiation that extend no further than a few millimeters. One benefit of this type of radiation treatment to destroy cancerous cells is that a higher level of local radiation can be applied directly to an area with minimal risk to patients.
Until the 20th century, glass objects were were typically produced in glass factories where skilled workers fabricated the pieces, based on the drawings of designers. In the 1960’s technological advances made it easier and more comfortable to work and manipulate glass. Artists, such as Hans Godo Fräbel and Harvey Littleton quickly discovered this new and enormous potential for glass. Independent from each other, both began to experiment artistically with glass in small group settings; consequently, the studio glass movement was born.
