Glass History: Modern Times
Task: You are working as a trainee at the glassmuseum in Rheinbach. The head of the press department has begged you and your colleagues to write a short overview on the history of glass for the catalogue of the permanent exhibition. Use the following text as a database and write a summary on glass in modern times. Put your text in the Glass Classroom.
If you don't know exactly how to summarize, open this worksheet: summary (beginners)
England: Lead crystal
The development of lead crystal has been attributed to the English glassmaker George Ravenscroft (1618-1681), who patented his new glass in 1674. He had been commissioned to find a substitute for the Venetian crystal produced in Murano and based on pure quartz sand and potash. By using higher proportions of lead oxide instead of potash, he succeeded in producing a brilliant glass with a high refractive index which was very well suited for deep cutting and engraving.
France: Mirror production
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.
From 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.
Schott
Abbe
Siemens
Increasing automation
Towards the end of the 19th century, the American engineer Michael Owens (1859-1923) invented an automatic bottle blowing machine which only arrived in Europe after the turn of the century. Owens was backed financially by E.D.L. Libbey, owner of the Libbey Glass Co. of Toledo, Ohio. By the year 1920, in the United States, there were around 200 automatic Owens Libbey Suction Blow machines operating. In Europe, smaller, more versatile machines from were also popular.
Further impetus was given to automatic production processes in 1923 with the development of the gob feeder, which ensured the rapid supply of more consistently sized gobs in bottle production. Soon afterwards, in 1925, individual section machines were developed. Used in conjunction with the gob feeders, these machines allowed the simultaneous production of a number of bottles from one piece of equipment. The gob feeder-IS machine combination remains the basis of most automatic glass container production today.
note: This is an abbreviated and simplified version of the glass history on http://www.glassonline.com
