"To make much better glass ..."
AHG - SGT Joint Study Day
The Development of British Crystal Glass in the 17th-century
Most histories of English glass give the credit for the development of British crystal
glass to the invention of glass containing lead oxide by George Ravenscroft in 1674.
This is wrong, so this paper sets out to get closer to the real story. It starts in 1632
during the tenure of the glass monopolist Sir Robert Mansell and spans the sixty
years it took for England and Ireland to become world-class glass exporters.
The figure shows a presumed English glass with a lion-mask moulded stem compared
with its Venetian cristallo equivalent and illustrates why Mansell needed to act.
This paper covers the introduction of Altarese glassmakers to London and the
progressive improvements they made, as documented by Christopher Merett
in his well-known commentary to Neri's Art of Glass and by Gustav Jung,
the Swedish glassmaker who visited London in 1667/8. Since lead oxide
had been used as an ingredient for alkali glasses on the continent for hundreds
of years it was clearly not invented in London, but the introduction of cheaper
saltpetre from India from 1673 provided the impetus for a range of English
crystal glass developments.
The paper argues that the glass patented by George
Ravenscroft was in fact a high-quality flint/borax/alkali glass by the Altarese
glassmaker John Odaccio Formica. Like all the other new crystal glasses made
using saltpetre this glass soon degraded. Lead oxide was probably introduced
into this mix in about 1675 to help cure this. Odaccio Formica then moved to
Dublin and for the next ten years London and Dublin were the main centres
for the production of this new "flint" glass. From the early 1680s the production of
lead glass spread throughout the country facilitated by Henry Holden's invention
of the closed pot.
Thus the development of British crystal glass was not a single event or the work
of a single individual, but was multi-threaded and took a life-time. This paper
summarises work by the author and his late wife Sue published in
in October 2014, April 2015 and April 2016.