Crown glass

Description

1) A hard, clear optical glass made of soda-lime. Crown glass has a low dispersion and a low refractive index.

2) An old form of window glass produced by spinning a globe of glass to form a thin, flat circle. The flattened sheet had a thicker raised center that was called a crown or bull's eye. Crown glass was made in France in the 17th century and was considered to be a high quality glass. It was typically a light blue or green color with a bright fire-polished finish. Circles were made with diameters up to 1.2 meters (44 inches). They were cut into smaller rectangular pieces for use.

Synonyms and Related Terms

2: verre en plats (Fr.); vidro de coroa ou prato (Port.); Normandy glass; bull's eye glass

Sources Checked for Data in Record

• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 361

• Walter C. McCrone, John Gustave Delly, The Particle Atlas, W. McCrone Associates, Chicago, IV, 1972

• Dictionary of Building Preservation, Ward Bucher, ed., John Wiley & Sons, Inc., New York City, 1996

• External source or communication Comment: G.Allen, L.Black,K.Hallam, "A Preliminary Investigation into the Effect of Solf-Adhesive Ultraviolet Absorbing Films on Window Glass" in ICOM preprints Lyon, 1999. p.757-763; EU dictionary