One of the earliest methods of glass window manufacture was the crown glass method. Hot blown glass was cut open opposite the pipe, then rapidly spun on a table before it could cool. Centrifugal force shaped the hot globe of glass into a round, flat sheet. The sheet would then be broken off the pipe and trimmed to form a rectangular window to fit into a frame.
At the center of a piece of crown glass, a thick remnant of the original blown bottle neck would remain, hence the name "bullseye." Optical distortions produced by the bullseye could be reduced by grinding the glass. The development of diaper latticed windows was in part because three regular diamond-shaped panes could be conveniently cut from a piece of Crown glass, with minimum waste and with minimum distortion.
This method for manufacturing flat glass panels was very expensive and could not be used to make large panes. It was replaced in the 19th century by the cylinder, sheet, and rolled plate processes, but it is still used in traditional construction and restoration.
Read more about this topic: Architectural Glass
Famous quotes containing the words crown and/or glass:
“There might you have beheld one joy crown another, so and in such manner that it seemed sorrow wept to take leave of them, for their joy waded in tears.”
—William Shakespeare (1564–1616)
“Here in the centre stands the glass. Light
Is the lion that comes down to drink. There
And in that state, the glass is a pool.
Ruddy are his eyes and ruddy are his claws
When light comes down to wet his frothy jaws”
—Wallace Stevens (1879–1955)