Crown glass


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crown glass

[′krau̇n ‚glas]
(materials)
A soda-lime glass, typically having 72% SiO2, 13% CaO, and 15% Na2O, which is hard and will take a simple polish; highly transparent for visible light.

Crown glass

1. An early form of window glass, cut from blown disks.
2. The glass made by blowing a mass of molten material, which is then flattened into a disk and spun into a cular sheet.
See also: Glass

crown glass

A handmade glass of soda-lime composition, used for windows; manufactured in the early 19th century by a now-obsolete process in which a hollow sphere of glass was blown while still very soft, then spun to form a large, nearly flat circular disk. During the spinning process, ripple lines were formed in a pattern of concentric circles, with their center at the center of the spun disk; this central area was used in a bull’s eye window. Also see glass.
References in periodicals archive ?
Pilkington plc originated in 1826 as the St Helens Crown Glass Company founded with the technical knowledge of John William Bell and finance from three of the most influential local families - the Bromilows, the Greenalls and the Pilkingtons.
Archaeological evidence which would support an occupation in the early 19th century includes coins and medals dating to the War of 1812 or earlier, creamware or "Old Blue" transferware ceramics, fragments of crown glass windows, blown and hand-moulded glass bottles, metal buttons stamped or cast from a mould, and gun parts related to this period.
The finger scanning window is a 13mm thick crown glass prism which is much more reliable and robust than semiconductor fingerprint sensor.