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History of Glass
From
our earliest origins, man has been making use of glass. Historians have
discovered that a form of natural glass - obsidian - formed for
instance, within the mouth of a volcano as a result of the intense heat
of an eruption melting sand - was first used by man as tips for spears.
Archaeologists
have found evidence of man-made glass which dates back to 4000BC; this
took the form of glazes used for coating stone beads. It was not until
1500 BC that the first hollow glass container was made by covering a
sand core with a layer of molten glass.
Glass
blowing became the most common way to make glass containers from the
First Century BC. However, the glass made during this time was highly
coloured due to the impurities of the raw material. It was not until the
First Century AD when colourless glass was produced and then coloured
by the addition of colouring materials.
The
secret of glass making came to Britain with the Romans. However, the
skills and technology required to make glass were closely guarded by the
Romans and it was not until the Roman Empire disintegrated that skills
for glass making spread throughout Europe and the Middle East.
The
Venetians, in particular, gained a reputation for technical skill and
artistic ability in the making of glass bottles and a fair number of the
city's craftsmen left Italy to set up glassworks throughout Europe.
In
Britain, there is evidence of a glass industry round Jarrow and
Wearmouth dating back to 680AD, while from the 13th Century, there is
evidence of there having been a glass industry in the Weald and the
afforested area of Surrey and Sussex around Chiddingford.
A
major milestone in the history of glass occurred with the invention of
lead crystal glass by George Ravenscroft. He attempted to counter the
effect of clouding that sometimes occurred in blown glass by introducing
lead to the raw materials used in the process.
The
new glass he created was softer and easier to decorate and had a higher
refractive index, adding to its brilliance and beauty, and it proved
invaluable to the optical industry. It's thanks to Ravenscroft's
invention that optical lenses, astronomical telescopes, microscopes and
the like became possible.
The
modern glass industry only really started to develop in Britain after
the repeal of the Excise Act in 1845 relieved the heavy taxation that
had been enforced. Before that time, excise duties were placed on the
amount of glass melted in a glasshouse and levied continuously from 1745
to 1845.
Joseph
Paxton's Crystal Palace at the Great Exhibition of 1851 marked the
beginning of the discovery of glass as a building material. The
revolutionary new building encouraged the use of glass in public,
domestic and horticultural architecture. Glass manufacturing techniques
also improved with the advancement of science and better technology.
By
1887 glass making developed from traditional mouth blowing to a
semi-automatic process when Ashley introduced a machine capable of
producing 200 bottles per hour in Castleford, Yorkshire - more than
three times quicker than the previous production methods.
Twenty
years later, in 1907, the first fully automated machine was developed
in America by Michael Owens from major glass manufacturers Owens of
Illinois, and used at its factory in Manchester, Illinois making 2,500
bottles per hour.
Other
developments followed rapidly, but it was not until the First World
War, when Britain became cut off from essential glass suppliers that
glass became part of the scientific sector. Up until then glass was seen
as a craft rather than a precise science.
Today,
glass making is a modern, hi-tech industry operating in a fiercely
competitive global market where quality, design and service levels are
critical to maintaining market share.
Modern
glass plants are capable of making millions of glass containers a day
in many different colours, but green, brown and clear remain the most
popular.
Few
of us can imagine modern life without glass. It features in almost
every aspect of our lives - in our homes, our cars and whenever we sit
down to eat or drink. Glass packaging is used for many products, wines,
spirits and beers all come in glass as do medicines and cosmetics not to
mention numerous foodstuffs.
With
increasing consumer concern for the environment, glass has again come
into its own proving to be an ideal material for recycling. Glass
recycling is good news for the environment. It saves used glass
containers being sent to landfill and less energy is needed to melt
recycled glass than to melt down raw materials, thus saving energy.
Recycling also reduces the need for raw materials to be quarried thus
saving precious resources.