Listen as curator Jane Shadel Spillman describes an uncut crown of glass. Window glass was one of the most needed products in the new United States, but it was expensive to import. Some window glass factories were started in New Jersey, New York, and New England in the early 19th century.
There were two methods of blowing window glass. One of them is reflected in this window. A large bubble of glass was blown and cut open. The blower rotated the glass rapidly, with repeated reheating, until centrifugal force caused it to become a flat disk. The disk was annealed (cooled) and then cut into panes of the required shape and size. The knob in the center, where the glass was attached to the pontil, was called a “bull’s-eye.”