Glass in the 18th century
The discovery of lead crystal galvanised the glass industry into a flurry of creativity as never before. This century, possibly more than any other, saw a bewildering proliferation of new styles, new techniques and above all decorative design of the highest order.
The brilliance of lead crystal is due to a higher refractive indexPeter Cooke Author caused by the lead content. Ordinary glass has a refractive index of n = 1.5, addition of lead produces a range up to 1.7. The heightened refractive index results in increased dispersion (the degree to which a medium separates light into its component spectra), as in a prism. Crystal cutting techniques create a brilliant, sparkling effect as each cut facet reflects and transmits light through the object.
These enhance properties, necessitated changes in style. The boss or knob of glass on the stem of a glass, is known as a KNOP. If the knop has a curved form, slender above and bulging out below, it is known as a ‘true baluster’. When used upside down, it’s designated as an ‘inverted baluster’. For for the next 35 years, the BALUSTER STEMS dominated the market, using designs cut into the bowl to enhance the brilliance.
The desire to cheapen the glass to please the less wealthy led to a decline in the quality of the metal used and the flamboyant styles gave way to glasses with smaller bowls and longer stems. This period of the BALUSTROID STEMS AND LIGHT BALUSTERS was to last from 1725-1765. The light balusters, better known as ‘Newcastle’ glasses, with their tall, slender, knopped stems had a far greater appeal than the earlier Balustroid stems. This style was pre-eminent from 1735-1765, when beautifully engraved glasses by Frans Greenwood, Jacob Snag and later David Wolff were in favour. The leading enamelers were William and Mary Beilby of Newcastle and last December a new world auction record was set for glass produced by an 18th-Century Tyneside craftsman. London auctioneers Bonhams sold a Prince William V of Orange goblet made by William Beilby for £117,000.
The largest group of remaining 18th century drinking glasses are the PLAIN STRAIGHT STEMS(1740-1770). The style was easy and cheap to turn out and was made in a variety of bowl shapes. During this period, AIR-TWIST STEMS were also produced for the quality market. There were also COMPOSITE STEMS.
Overlapping this period from 1750 – 1780 were the OPAQUE WHITE TWIST STEMS often with engraved bowls and from 1755 – 1775 the MIXED AND COLOURED TWIST STEMS.
JACOBITE AND WILLIAMITE GLASS was produced in profusion during the mid-18th century to support the causes. Jacobite emblems were usually the rose with usually six petals and one or two buds. One very special type was the so-called AMEN glasses
In 1777 and again in 1780 changes in the Excise Act resulted in the doubling of duty in England, but Ireland was granted free trade. Although there was already a large industry in Ireland, many English firms set up there and prospered. This period of grace lasted until 1845 when the Excise acts were repealed.
1760-1800 FACETED STEMS – diamond or hexagonal-shaped facets were the favourites, but vertical fluting and scale cutting were also used.
Inevitably there was some run over in styles from different manufacturers and faceted stems were still produced into the new century.