Glass making has a fascinating history, which I’ll show you here.
Probably, the first glass was obsidian, a volcanic rock which is translucent and would have been easy to find. There is for instance evidence that in Turkey in the Middle Paleolithic, it was used to make tools. However, the historian Pliny wrote that glass was made by accident about 5000 years ago, when some people heated sand.
The recipe for making glass is still the same today, requiring little except silica, soda ash and heat. Glass bottles were made in Egypt by 1500BC. Some of these have been found in the tombs of Phaeroes, like Thutmose III. They created the bottles by the “core-base” method, in which iron rods with cores of silica paste are dipped repeatedly into molten glass. The Egyptians also made glazes for their ceramics by heating crushed quartz.
The Babylonians switched the methodology of making glass when they changed the rods to hollow ones. They discovered at this point that they could blow through the rods to make the glass. This method is dated to around 250BC, and made glass very inexpensive to create; Pliny the Elder noted that glass cups were starting to replace other, more expensive ones, in Rome.
When the Roman Empire collapsed, glassmaking pretty much disappeared in Europe. The only windows we have from that time through the middle of the Medieval Era are the expensive stained glass ones of the Gothic Era monasteries.
When the Italians started to trade with Byzantium in the 13th and 14th centuries, glassmaking made a comeback in Venice. The English added lead oxide to the original formula and thus were able to create more solid and durable vessels. But even through the 17th and 18th centuries, glass was only used for windows as little squares.
In 1608 in Virginia, the first glassmaking plant was started. Other companies soon followed like the Sandwich Glass Company which started in 1825. These glassmakers created the lovely bowls and cups you can still find in museums. The Worcester Art Museum, for instance, has a large exhibit of early American glassware, much of it from Sandwich.
Glass was used for numerous things in America, including whiskey and apothecary bottles and flasks. Crown glass was the name for glass used in windows, and was made by blowing through a hot rod, then spinning it, which left a bump in the pane, hence the name. By 1825 though, the cylinder method was introduced, in which glass was blown through a rod to make a cylinder which when sliced down one side folded out into a flat pane. After that, glass was used for other things, like mirrors.
THE MODERN AGE OF GLASSMAKING
Glass is now very commonplace in the world. The computer screen you’re staring at is a sort of glass. The mirror in everyone’s bathroom is glass. Some of your cups probably are glass, and you might have some fake gems that are cubic zirconium, a different kind of glass which looks pretty and is much cheaper than the real thing.
New and interesting methods of making glass are still being thought up. Natural gas and petroleum are now used as fuel, which affects the method only in that it makes glassmaking extremely cheap to do. Chemical changes to the formula have made it better and safer to create and use, which is especially important now due to the technology used everywhere.
Fiberglass was created by the automobile industry to begin with, but now it’s used for many things such as computer screens and sheathing for buildings. Polychrome, a form of fiberglass, is now used for making prescription glasses, and is very tough. I have a pair of such glasses myself, and can say definitely that they’re hard to scratch or break!
Recycling glass and remaking it requires a process of grinding down the old material, and then re-blowing it. This is a very simple process, and popular nowadays because people are thinking more about their planet. Remaking the glass into other containers requires sand, soda, or limestone, depending on what’s needed. Since glass never deteriorates, this is a very sensible thing to do.
Glass is a lovely thing, and its creation something much more interesting than it seems at first. Sometime, think as you go around your house of all the things you use in a day that are of glass or fiberglass. Or go to the museum and look at the exhibits of glass in old times, back when glass was still a new and amazing thing.