Title: Trefoil Bowl, about 1800
Moses Myers House, Chrysler Museum of Art.
Lead (II) Oxide
In 1676, George Ravenscroft discovered that the addition of lead oxide (PbO) adds clarity to glass. Lead, a heavy metal, increases the density of the glass, which in turn raises its refractive index. Light waves pass more slowly through it, so some light is reflected back from the surface, giving lead glass its prized sparkle.
Lead glass is relatively soft, and its surface can be easily cut to amplify the effects of light. PbO also provides a wider softening range and gives the glassblower added time to shape his vessels.
This lead glass bowl is part of a full table service that belonged to Moses Myers, a wealthy Norfolk merchant who lived in the early 1800s. At that time, high-quality glass was imported from Europe.