Colin is an engineer by training. He served a six-year apprenticeship, has a Master of Science degree, a Diploma in Engineering Management and is a Chartered Engineer. In 2002 he was elected a QinetiQ Fellow for his work on system engineering verification (have we built the thing right?) and validation (have we built the right thing?). In 2004 he founded his own specialist company which worked internationally for 10 years.Currently president of the Association for the History of Glass he has written and lectured on a variety of glass-history topics, particularly the development of British Crystal glass in the sixty years 1642-1702. Colin & Sue had three papers on this field published Glass Technology. Sadly Sue died of cancer in 2006 and did not live to see the last one in print. Colin’s second wife Sylvia who was helping write a fourth paper has sadly also recently died of motor neurone disease.
A quest for better and vheaper flint glass
Private Researcher, President Association for the History of Glass,
10 College Street, Salisbury, SP1 3AL
On 15th June, 1674 The Venetian Secretary wrote:
“The glass trade also might revive though it now suffers from the extreme beauty of the English drinking glasses. They are very white and thick, in imitation of rock crystal, but very far from real perfection though they strike the eye and surpass those of Venice. In spite of this they are soft, fragile and extremely dear and so I do not doubt that Venetian produce might yet resume first place.”
Some months earlier a Mr Swanborne had bought two of these early crystal drinking glasses for the sum of three shillings. Twenty years on in 1695 a petition boasted that the: “Makers of Flint Glasses …” had “long since beaten out all Foreigners, … merely by making those Commodities better and underselling them”. Since Mr Swanborne’s three shilling outlay would then have bought him six double-flint wine glasses, they were undoubtedly much cheaper. By then the manufacture of flint, green and ordinary glass represented nearly half of the total output of the English glass industry. The quote already talks about glasses as being commodities – articles of trade; advantageous; useful and convenient. With an estimated annual production of around six million glasses, thirty percent of the value of which was exported, English glassmaking was already a mature industry and ripe for taxation.
However that leaves the mere detail of how glassmakers managed to achieve such a large price reduction with products that were then seen as being consistently better than the competition. This paper looks at some of the technology they used to achieve this better, cheaper glass. This includes reference to some recent glassmaking-residue finds attributed to the Old Bedlam glasshouse in London. Analysis of these suggests that this glasshouse was an early user of closed glassmaking pots. The paper will thus look at three areas that have been informed by these new finds: the challenge of fining the batch after the switch to closed pots; glass-waste reuse within the glasshouse; and controlling the colour of the white (“colourless”) glass.
The industrial revolution is normally seen as starting more than 50 years after the period under discussion here, but for glass it is arguable that it was industrial evolution, not revolution. Thus the kind of technological evolution discussed here was a vital part of establishing an English ‘flint, green and ordinary’ glass business that would endure with little change for nearly two centuries.